Magnetic head with textured surfaces

ABSTRACT

A method according to one embodiment includes contacting an oxidant with an AlTiC portion of a magnetic head for recessing TiC grains of the AlTiC portion. A method according to another embodiment includes contacting a peroxide with an AlTiC portion of a magnetic head for recessing TiC grains of the AlTiC portion from a media bearing surface of the AlTiC portion. A magnetic head according to yet another embodiment includes an AlTiC portion having a media bearing surface; and a thin film portion coupled to the AlTiC portion, wherein TiC grains of the AlTiC portion are recessed from the media bearing surface.

BACKGROUND

The present invention relates to data storage systems, and moreparticularly, this invention relates to textured surfaces on a magnetichead.

In magnetic storage systems, data is read from and written onto magneticrecording media utilizing magnetic transducers commonly. Data is writtenon the magnetic recording media by moving a magnetic recordingtransducer to a position over the media where the data is to be stored.The magnetic recording transducer then generates a magnetic field, whichencodes the data into the magnetic media. Data is read from the media bysimilarly positioning the magnetic read transducer and then sensing themagnetic field of the magnetic media. Read and write operations may beindependently synchronized with the movement of the media to ensure thatthe data can be read from and written to the desired location on themedia.

An important and continuing goal in the data storage industry is that ofincreasing the density of data stored on a medium. For tape storagesystems, that goal has led to increasing the track density on recordingtape, and decreasing the thickness of the magnetic tape medium. However,the development of small footprint, higher performance tape drivesystems has created various problems in the design of a tape headassembly for use in such systems.

In a tape drive system, magnetic tape is moved over the surface of thetape head at high speed. This movement generally entrains a film of airbetween the head and tape. Usually the tape head is designed to minimizethe spacing between the head and the tape. The spacing between themagnetic head and the magnetic tape is crucial so that the recordinggaps of the transducers, which are the source of the magnetic recordingflux, are in near contact with the tape to effect efficient signaltransfer, and so that the read element is in near contact with the tapeto provide effective coupling of the magnetic field from the tape to theread element.

Thin film magnetic heads are fabricated by building thin film devices ona ceramic substrate commonly referred to as a “wafer.” Common wafermaterials include alumina-titanium carbide (Al₂O₃—TiC) composites,collectively referred to as AlTiC, and which are generally electricallyconductive and typically comprise approximately 30-35% by weight TiC.

After polishing and other processing, the TiC grains 302 in a wafersubstrate 306 of a new magnetic head typically protrude above thesurrounding alumina 304 as illustrated in FIG. 3A. The TiC grains 302may protrude above the surface 308 of the surrounding alumina 304 by adistance a of approximately 7 nm and the surface roughness (“Ra”) may bebetween approximately 2 nm to approximately 3 nm. The TiC grains 302 areconsiderably harder than the alumina 304 of the wafer substrate 306.

After a short period of tape contact during use, the TiC grains 302 tendto wear quickly to about the level 308 of the alumina due to mechanicalshearing and oxidation as illustrated in FIG. 3B. Here, the Ra can dropto below 1 nm. At this point, undesirable head-to-tape interface (HTI)stiction forces are believed to be the highest.

Stiction forces at the HTI of a tape drive are a significant issue. Thestiction forces can be so high that a drive cannot move the tape duringoperation. If excessive force is used to move the tape, the tape may bedamaged or even break. In addition, if TiC grains protruding from thesurrounding alumina break off of the surface of the wafer substrateduring use, the separated TiC particles may be pushed through the sensorarea by the tape, causing shorting and premature head wear. Therefore, abetter way of avoiding the problems caused by stiction would bebeneficial.

SUMMARY

A method according to one embodiment includes contacting an oxidant withan AlTiC portion of a magnetic head for recessing TiC grains of theAlTiC portion.

A method according to another embodiment includes contacting a peroxidewith an AlTiC portion of a magnetic head for recessing TiC grains of theAlTiC portion from a media bearing surface of the AlTiC portion.

A magnetic head according to yet another embodiment includes an AlTiCportion having a media bearing surface; and a thin film portion coupledto the AlTiC portion, wherein TiC grains of the AlTiC portion arerecessed from the media bearing surface.

A magnetic head according to yet another embodiment includes an AlTiCportion having a media-facing surface; and a thin film portion coupledto the AlTiC portion, wherein TiC grains of the AlTiC portion arerecessed from the media bearing surface, wherein the media bearingsurface of the AlTiC portion is primarily Al-containing grains.

Any of these embodiments may be implemented in a magnetic data storagesystem such as a tape drive system, which may include a magnetic head, adrive mechanism for passing a magnetic medium (e.g., recording tape)over the magnetic head, and a controller electrically coupled to themagnetic head.

Other aspects and embodiments of the present invention will becomeapparent from the following detailed description, which, when taken inconjunction with the drawings, illustrate by way of example theprinciples of the invention.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a schematic diagram of a simplified tape drive systemaccording to one embodiment.

FIG. 2 illustrates a side view of a flat-lapped, bi-directional,two-module magnetic tape head according to one embodiment.

FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.

FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.

FIG. 2C is a detailed view of a partial tape bearing surface of a pairof modules.

FIG. 3A is a prior art drawing depicting a media surface of a substrateprior to use thereof.

FIG. 3B is a prior art drawing depicting a media surface of a substrateafter use thereof.

FIG. 4 is a drawing depicting recessed TiC grains near a media surfaceof a substrate according to one embodiment.

DETAILED DESCRIPTION

The following description is made for the purpose of illustrating thegeneral principles of the present invention and is not meant to limitthe inventive concepts claimed herein. Further, particular featuresdescribed herein can be used in combination with other describedfeatures in each of the various possible combinations and permutations.

Unless otherwise specifically defined herein, all terms are to be giventheir broadest possible interpretation including meanings implied fromthe specification as well as meanings understood by those skilled in theart and/or as defined in dictionaries, treatises, etc.

It must also be noted that, as used in the specification and theappended claims, the singular forms “a,” “an” and “the” include pluralreferents unless otherwise specified.

The following description discloses several preferred embodiments oftape-based storage systems, as well as operation and/or component partsthereof.

In one general embodiment, a method includes contacting an oxidant withan AlTiC portion of a magnetic head for recessing TiC grains of theAlTiC portion.

In another general embodiment, a method includes contacting a peroxidewith an AlTiC portion of a magnetic head for recessing TiC grains of theAlTiC portion from a media bearing surface of the AlTiC portion.

In another general embodiment, a magnetic head includes an AlTiC portionhaving a media bearing surface; and a thin film portion coupled to theAlTiC portion, wherein TiC grains of the AlTiC portion are recessed fromthe media bearing surface.

In another general embodiment, a magnetic head includes an AlTiC portionhaving a media-facing surface; and a thin film portion coupled to theAlTiC portion, wherein TiC grains of the AlTiC portion are recessed fromthe media bearing surface, wherein the media bearing surface of theAlTiC portion is primarily Al-containing grains.

FIG. 1 illustrates a simplified tape drive 100 of a tape-based datastorage system, which may be employed in the context of the presentinvention. While one specific implementation of a tape drive is shown inFIG. 1, it should be noted that the embodiments described herein may beimplemented in the context of any type of tape drive system.

As shown, a tape supply cartridge 120 and a take-up reel 121 areprovided to support a tape 122. One or more of the reels may form partof a removable cassette and are not necessarily part of the system 100.The tape drive, such as that illustrated in FIG. 1, may further includedrive motor(s) to drive the tape supply cartridge 120 and the take-upreel 121 to move the tape 122 over a tape head 126 of any type.

Guides 125 guide the tape 122 across the tape head 126. Such tape head126 is in turn coupled to a controller assembly 128 via a cable 130. Thecontroller 128 typically controls head functions such as servofollowing, writing, reading, etc. The cable 130 may include read/writecircuits to transmit data to the head 126 to be recorded on the tape 122and to receive data read by the head 126 from the tape 122. An actuator132 controls position of the head 126 relative to the tape 122.

An interface 134 may also be provided for communication between the tapedrive and a host (integral or external) to send and receive the data andfor controlling the operation of the tape drive and communicating thestatus of the tape drive to the host, all as will be understood by thoseof skill in the art.

By way of example, FIG. 2 illustrates a side view of a flat-lapped,bi-directional, two-module magnetic tape head 200 which may beimplemented in the context of the present invention. As shown, the headincludes a pair of bases 202, each equipped with a module 204, and fixedat a small angle α with respect to each other. The bases are typically“U-beams” that are adhesively coupled together. Each module 204 includesa substrate 204A and a closure 204B with a gap comprising elements 206such as readers and/or writers situated therebetween. In use, a tape 208is moved over the modules 204 along a media (tape) bearing surface 209in the manner shown for reading and writing data on the tape 208 usingthe readers and writers. The wrap angle θ of the tape 208 at edges goingonto and exiting the flat media support surfaces 209 are usually between⅛ degree and 4½ degrees.

The substrates 204A are typically constructed of a wear resistantmaterial, such as a ceramic. The closures 204B made of the same orsimilar ceramic as the substrates 204A.

The readers and writers may be arranged in a piggyback configuration.The readers and writers may also be arranged in an interleavedconfiguration. Alternatively, each array of channels may be readers orwriters only. Any of these arrays may contain one or more servo readers.

FIG. 2A illustrates the tape bearing surface 209 of one of the modules204 taken from Line 2A of FIG. 2. A representative tape 208 is shown indashed lines. The module 204 is preferably long enough to be able tosupport the tape as the head steps between data bands.

In this example, the tape 208 includes 4-22 data bands, e.g., with 16data bands and 17 servo tracks 210, as shown in FIG. 2A on a one-halfinch wide tape 208. The data bands are defined between servo tracks 210.Each data band may include a number of data tracks, for example 96 datatracks (not shown). During read/write operations, the elements 206 arepositioned within one of the data bands. Outer readers, sometimes calledservo readers, read the servo tracks 210. The servo signals are in turnused to keep the elements 206 aligned with a particular track during theread/write operations.

FIG. 2B depicts a plurality of read and/or write elements 206 formed ina gap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the arrayof elements 206 includes, for example, 16 writers 214, 16 readers 216and two servo readers 212, though the number of elements may vary.Illustrative embodiments include 8, 16, 32, and 64 elements 206 perarray. A preferred embodiment includes 32 readers per array and/or 32writers per array. This allows the tape to travel more slowly, therebyreducing speed-induced tracking and mechanical difficulties. While thereaders and writers may be arranged in a piggyback configuration asshown in FIG. 2B, the readers 216 and writers 214 may also be arrangedin an interleaved configuration. Alternatively, each array of elements206 may be readers or writers only, and the arrays may contain one ormore servo readers 212. As noted by considering FIGS. 2 and 2A-Btogether, each module 204 may include a complementary set of elements206 for such things as bi-directional reading and writing,read-while-write capability, backward compatibility, etc.

FIG. 2C shows a partial tape bearing surface view of complimentarymodules of a magnetic tape head 200 according to one embodiment. In thisembodiment, each module has a plurality of read/write (R/W) pairs in apiggyback configuration formed on a common substrate 204A and anoptional electrically insulative layer 236. The writers, exemplified bythe write head 214 and the readers, exemplified by the read head 216,are aligned parallel to a direction of travel of a tape mediumthereacross to form an R/W pair, exemplified by the R/W pair 222.

Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. TheR/W pairs 222 as shown are linearly aligned in a direction generallyperpendicular to a direction of tape travel thereacross. However, thepairs may also be aligned diagonally, etc. Servo readers 212 arepositioned on the outside of the array of R/W pairs, the function ofwhich is well known.

Generally, the magnetic tape medium moves in either a forward or reversedirection as indicated by arrow 220. The magnetic tape medium and headassembly 200 operate in a transducing relationship in the mannerwell-known in the art. The piggybacked MR head assembly 200 includes twothin-film modules 224 and 226 of generally identical construction.

Modules 224 and 226 arc joined together with a space present betweenclosures 204B thereof (partially shown) to form a single physical unitto provide read-while-write capability by activating the writer of theleading module and reader of the trailing module aligned with the writerof the leading module parallel to the direction of tape travel relativethereto. When a module 224, 226 of a piggyback head 200 is constructed,layers are formed in the gap 218 created above an electricallyconductive substrate 204A (partially shown), e.g., of AlTiC, ingenerally the following order for the R/W pairs 222: an insulating layer236, a first shield 232 typically of an iron alloy such as NiFe(permalloy), CZT or Al—Fe—Si (Sendust), a sensor 234 for sensing a datatrack on a magnetic medium, a second shield 238 typically of anickel-iron alloy (e.g., 80/20 Permalloy), first and second writer poletips 228, 230, and a coil (not shown).

The first and second writer poles 228, 230 may be fabricated from highmagnetic moment materials such as 45/55 NiFe. Note that these materialsare provided by way of example only, and other materials may be used.Additional layers such as insulation between the shields and/or poletips and an insulation layer surrounding the sensor may be present.Illustrative materials for the insulation include alumina and otheroxides, insulative polymers, etc.

In some embodiments, a method may include preprofiling (e.g., prior touse) the substrate surface of a thin film magnetic head for magneticwriting and/or reading (such as in a tape drive, hard disk drive, etc.)to minimize undesirable stiction forces without otherwise changing thehead surface. Also, in some embodiments, a method may include reducingthe potential for free body particles to break off the substratesurface, which can damage the head or lead to premature head wear. Whilethe descriptions included herein are described with reference topreprofiling substrates for heads used in tape drives, it is understoodthat the descriptions included herein are applicable to substrates usedfor other purposes, including substrates used to fabricate heads forother types of magnetic storage drives.

FIG. 4 illustrates a preferred profile of a ceramic wafer substrate 406from which a thin film magnetic head may be fabricated according to oneembodiment. As discussed above, common wafer materials includealumina-titanium carbide (Al₂O₃—TiC) composites, which typicallycomprise about 30-35% by weight TiC. While the descriptions includedherein are described with reference to alumina-titanium carbidecomposite substrates, it is understood that the descriptions includedherein are not limited to alumina-titanium carbide composites and areapplicable to other wafer substrate materials.

The surface 408 of the wafer substrate 406 corresponds to the surface ofthe tape head that will be facing the tape during operation. The surface408 is preprofiled prior to use in a tape drive or the like so that theTiC grains 402 are recessed below the surface 408 of the surroundingalumina 404 by a predetermined depth β such that stiction and frictionforces are sufficiently minimized.

In one embodiment, a method to reduce stiction and friction forces bypreprofiling the tape bearing surface includes contacting an oxidantwith an AlTiC portion of a magnetic head for recessing TiC grains 402 ofthe AlTiC portion. This may include a chemical etching process, whereexposed TiC grains 402 at the surface 408 of the substrate 406 may bedissolved after being soaked for a period of time in the oxidant. Inthis and other embodiments, recessing TiC grains 402 may include bothrecession of TiC grains 402 by removal of a portion thereof, as well ascomplete removal of TiC grains 402 near the surface 408 of the wafersubstrate 406. Note that the resultant profile of the AlTiC substrateafter the etching or removal process is fairly benign since the headeventually reaches this profile after a sufficient amount of tape wearduring use of the head.

Any type of oxidant may be used. In some preferred embodiments, theoxidant may be a peroxide, as would be known to one of skill in the art,such as hydrogen peroxide, magnesium peroxide, etc.

In some approaches, the oxidant may be selected from a group consistingof a hypohalite compound such as hypochlorite, a halogen such as iodine,a halogen compound such as chlorite, chlorate, perchlorate, and otheranalogous halogen compounds, a permanganate salt, ammonium cerium (IV)nitrate, a hexavalent chromium compound (such as chromic acids,dichromic acids, and chromium trioxide), Pyridinium chlorochromate(PCC), and chromate/dichromate compounds, Tollen's Reagent, a sulfoxide,persulfuric acid, ozone, osmium tetroxide (OsO₄), nitric acid, nitrousoxide (N₂O), etc.

In some more approaches, the oxidant may be present in a liquidcomposition, wherein a reaction product of the TiC with the oxidantdissolves into the liquid composition.

In even more approaches, mixtures of oxidants may also be used.

It should be noted that if the write/read elements may react negativelyto chemical etching, the active region of the head can be protectedprior to the etching process by applying a coating thereover, such as acarbon coating, photoresist, or some other coating. It may also beadvantageous to use such a coating to prevent certain regions frometching so that some portions of the head are left with a well-knownhead-tape-interface while other portions have a roughened surface. Theroughened surfaces will still significantly reduce stiction.

Because stiction and friction forces depend upon the surface of themedia (e.g., tape), humidity, media lubrication and other factors, thepredetermined depth β may vary depending on these factors, but isintended to be a depth such that the stiction and friction forces duringdrive operation are sufficiently minimized. In some preferredembodiments, the TiC grains 402 may be recessed below the surface 408 ofthe surrounding alumina 404 by a depth β between approximately 1 nm toin excess of approximately 30 nm, and more preferably betweenapproximately 15 nm and approximately 20 nm. In some preferredapproaches, the TiC grains 402 may be recessed at least 5 nm,alternatively at least 10 nm, from a media bearing surface 408 of theAlTiC portion. The surface roughness Ra may be preferably between about5 nm and about 7 nm.

The recession can be measured for sample holes individually orcumulatively, can be measured relative to a plane extending along amedia bearing surface 408 of the AlTiC portion, etc. In one approach,such a plane may be discerned, for example, by placing the media bearingsurface 408 on an optical flat or other flat surface after the etching.

By preprofiling the surface 408 of the wafer substrate 406 prior to use,undesirable stiction forces at the head-to-tape interface (HTI) areminimized without otherwise modifying the head surface (e.g., beveling,roughening and/or patterning), which can have adverse affects, causeperformance degradations, and increase costs and manufacturing time. Inaddition, such preprofiling of the surface 408 of the wafer substrate406 reduces the TiC material near the surface 408 such that the amountof undesirable free body particles at the HTI is minimized.

Other methods may be utilized to preprofile the surface 408 of thesubstrate 406 so that the TiC grains 402 are recessed below the surfaceof the surrounding alumina 404. For example, the surface 408 of thewafer substrate 406 may be preprofiled using conventional ion milling orsputtering techniques in which an ion beam is directed on the TiC grains402 protruding from the surface 408. Portions of the TiC grains 402exposed to the ion beam may be eroded due to transfer of momentum fromthe ions to the TiC particles 402 constituting the exposed surface. Theion beam may be produced by any method known to one of skill in the art,such as an ion gun in which a suitable gas, such as argon, is ionized byelectron impact and in which the ions so produced are acceleratedthrough a stationary electric field.

Similarly, a reactive ion etching (“RIE”) process may be used accordingto some embodiments to preprofile the surface 408 of the substrate 406by using chemically reactive plasma to etch or otherwise remove portionsof the exposed TiC grains 402 from the surrounding alumina 404 at thesurface 408. The plasma may be generated in a vacuum by anelectromagnetic field and high energy ions from the plasma may reactwith the exposed TiC grains 402 on the surface 408.

Also, in some embodiments, a method for preprofiling the surface 408 ofthe substrate 406 may include contacting a peroxide with an AlTiCportion of a magnetic head for recessing TiC grains 402 of the AlTiCportion from a media bearing surface 408 of the AlTiC portion.

In addition, in some embodiments, the peroxide may be present in aliquid composition, wherein a reaction product of the TiC with theoxidant dissolves into the liquid composition.

In another approach, the TiC grains 402 may be recessed by a sufficientamount, e.g., 10 nm, from the media bearing surface 408 to minimizestiction.

The surface 408 of the substrate 408 may also be preprofiled to recessexposed TiC grains 402 below the surrounding alumina 404 by runningabrasive media (e.g., chromium, diamond tape, diamond like carbon (DLC),etc.) over the surface 408 in some embodiments.

While various methods for preprofiling the surface 408 of the wafersubstrate 406 have been described, it is understood that this inventionis not limited to the specific methods described herein and that otherpreprofiling techniques may be utilized to recess exposed TiC grains 402below the surface of the surrounding alumina 404. Moreover, combinationsof the foregoing may also be used.

In some different embodiments, the methods described above may beincluded in the development of a magnetic head. For example, in someembodiments, a magnetic head may comprise an AlTiC portion 406 having amedia bearing surface 408. Also, the magnetic head may include a thinfilm portion coupled to the AlTiC portion 406, wherein TiC grains 402 ofthe AlTiC portion 406 may be recessed from the media bearing surface408. Accordingly, the media bearing surface 408 of the AlTiC portion 406is primarily or entirely Al-containing material (excluding impurities).

In some additional embodiments, sidewalls of the Al-containing grainsadjacent the media bearing surface 408 may have shapes and/ororientations characteristic of dissolution of material previouslypositioned therebetween as opposed to shadowing, redeposition, etc.,that is characteristic of dry etching.

In some more approaches, the AlTiC portion 406 may be a substrate of thethin film portion, and the magnetic head may further comprise a closurecoupled to the thin film portion, the closure being formed of AlTiC,wherein TiC grains of the closure are recessed from a media bearingsurface of the closure. In some embodiments, the AlTiC portion may be aclosure.

In another embodiment, the AlTiC portion 406 may be at least one of aclosure and a substrate of the thin film portion.

Having described and illustrated the principles of this application byreference to one or more preferred embodiments, it should be apparentthat the preferred embodiment(s) may be modified in arrangement anddetail without departing from the principles disclosed herein and thatit is intended that the application be construed as including all suchmodifications and variations insofar as they come within the spirit andscope of the subject matter disclosed herein.

While various embodiments have been described above, it should beunderstood that they have been presented by way of example only, and notlimitation. Thus, the breadth and scope of a preferred embodiment shouldnot be limited by any of the above-described exemplary embodiments, butshould be defined only in accordance with the following claims and theirequivalents.

What is claimed is:
 1. A magnetic head, comprising: an AlTiC portionhaving a media bearing surface; and a thin film portion coupled to andextending directly from the AlTiC portion, wherein exposed media facingsides of TiC grains of the AlTiC portion are physically recessed fromthe media bearing surface by at least 10 nm, the recession of the mediafacing sides of the TiC grains of the AlTiC portion being for minimizingfriction and stiction forces.
 2. A head as recited in claim 1, whereinthe media facing sides of the TiC grains are recessed at least 15 nmfrom the media bearing surface.
 3. A head as recited in claim 1, whereinthe media facing sides of the TiC grains are recessed approximately 15to approximately 20 nm from the media bearing surface.
 4. A head asrecited in claim 1, wherein sidewalls of Al-containing grains of theAlTiC portion at ends of the sidewalls immediately adjacent the mediabearing surface have shapes or orientations characteristic ofdissolution of material previously positioned therebetween.
 5. A datastorage system, comprising: a magnetic head as recited in claim 4; adrive mechanism for passing a magnetic medium over the magnetic head;and a controller electrically coupled to the magnetic head.
 6. A head asrecited in claim 1, wherein the AlTiC portion is a substrate of the thinfilm portion, and further comprising a closure coupled to the thin filmportion, the closure being formed of AlTiC, wherein media facing sidesof TiC grains of the closure are recessed from a media bearing surfaceof the closure.
 7. A head as recited in claim 1, wherein the AlTiCportion is a closure.
 8. A head as recited in claim 1, wherein a surfaceroughness of the AlTiC portion is between about 5 nm and about 7 nm. 9.A head as recited in claim 1, wherein the media facing sides of the TiCgrains are recessed in excess of approximately 30 nm from the mediabearing surface.
 10. A data storage system, comprising: a magnetic headas recited in claim 1; a drive mechanism for passing a magnetic mediumover the magnetic head; and a controller electrically coupled to themagnetic head.
 11. A head as recited in claim 1, wherein a corner of theAlTiC portion is defined by an intersection of the media bearing surfaceand a side of the AlTiC portion oriented perpendicular to the mediabearing surface, wherein a media facing side of a layer immediatelyadjacent the AlTiC portion is recessed from the tape media bearingsurface, wherein the side of the AlTiC portion positioned above themedia facing side of the layer is exposed.
 12. A magnetic tape head,comprising: an AlTiC portion having a tape bearing surface; and a thinfilm portion coupled to the AlTiC portion, wherein exposed media facingsides of TiC grains of the AlTiC portion are physically recessed fromthe tape bearing surface by at least 10 nm, the recession of the mediafacing sides of the TiC grains of the AlTiC portion being for minimizingfriction and stiction forces, wherein the tape bearing surface of theAlTiC portion is primarily Al-containing grains, wherein the AlTiCportion is a substrate of the thin film portion, and further comprisinga closure coupled to the thin film portion on an opposite side thereofthan the substrate, the thin film portion extending from the substrateto the closure.
 13. A head as recited in claim 12, wherein media facingsides of the TiC grains are recessed at least 15 nm from the tapebearing surface.
 14. A head as recited in claim 12, wherein the closureis formed of AlTiC, wherein media facing sides of TiC grains of theclosure are recessed from a tape bearing surface of the closure.
 15. Ahead as recited in claim 12, wherein a surface roughness of the AlTiCportion is between about 5 nm and about 7 nm.
 16. A head as recited inclaim 12, wherein the media facing sides of the TiC grains are recessedin excess of approximately 30 nm from the tape bearing surface.
 17. Ahead as recited in claim 12, wherein a corner of the AlTiC portion isdefined by an intersection of the tape bearing surface and a side of theAlTiC portion oriented perpendicular to the tape bearing surface,wherein a media facing side of a layer immediately adjacent the AlTiCportion is recessed from the tape bearing surface, wherein the side ofthe AlTiC portion positioned above the media facing side of the layer isexposed.
 18. A head as recited in claim 12, wherein sidewalls ofAl-containing grains of the AlTiC portion at ends of the sidewallsimmediately adjacent the tape bearing surface have shapes ororientations characteristic of dissolution of material previouslypositioned therebetween.
 19. A data storage system, comprising: amagnetic head as recited in claim 18; a drive mechanism for passing amagnetic medium over the magnetic head; and a controller electricallycoupled to the magnetic head.